This invention relates generally to fiber optic rotation sensors and particularly to reducing sensitivity of such sensors to radiation environments. Still more particularly, this invention relates to photobleaching the sense coil of a fiber optic rotation sensor system to reduce sensitivity to radiation.
A typical fiber optic gyro uses a long length of polarization maintaining (PM) fiber as a sense element for rotation. It has been shown that this type of fiber is sensitive to radiation environments. When exposed to ionizing radiation, the fiber develops color centers that attenuate light propagating through the sense coil. If enough attenuation occurs, the random walk of the gyroscope will increase significantly. When the attenuation is extremely high due to large doses of ionizing radiation, the gyroscope will lose all signals.